﻿<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>PanelLayout GoJS Sample</title>
  <meta name="description" content="Example custom PanelLayout." />
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <!-- Copyright 1998-2019 by Northwoods Software Corporation. -->

  <script src="../release/go.js"></script>
  <script src="../assets/js/goSamples.js"></script>  <!-- this is only for the GoJS Samples framework -->
  <script id="code">
    function init() {
      if (window.goSamples) goSamples();  // init for these samples -- you don't need to call this

      var $ = go.GraphObject.make;  // for conciseness in defining templates

      myDiagram = $(go.Diagram, "myDiagramDiv",  // create a Diagram for the DIV HTML element
        {
          "undoManager.isEnabled": true  // enable undo & redo
        });

      function PanelLayoutCascading() {
        go.PanelLayout.call(this);
      }
      go.Diagram.inherit(PanelLayoutCascading, go.PanelLayout);

      /**
       * Given the available size, measure the Panel and
       * determine its expected drawing size. Sets the measuredBounds of the object.
       *
       * This must call {@link #measureElement} with each Panel element.
       *
       * This must also construct the union.width and union.height of the passed in union Rect argument.
       *
       * @this {PanelLayout}
       * @param {Panel} panel Panel which called this layout
       * @param {number} width expected width of the panel
       * @param {number} height expected width of the panel
       * @param {Array.<GraphObject>} elements Array of Panel elements
       * @param {Rect} union rectangle to contain the expected union bounds of every element in the Panel. Useful for arrange.
       * @param {number} minw minimum width of the panel
       * @param {number} minh minimum height of the panel
       */
      PanelLayoutCascading.prototype.measure = function(panel, width, height, elements, union, minw, minh) {
        var l = elements.length;
        for (var i = 0; i < l; i++) {
          var elem = elements[i];
          this.measureElement(elem, width, height, minw, minh);
          var mb = elem.measuredBounds;
          union.width += mb.width;
          union.height += mb.height;
        }
      }


      /**
       * Given the panel and its list of elements, arrange each element.
       *
       * This must call {@link #arrangeElement} with each Panel element, which will set that element's {@link GraphObject#actualBounds}.
       *
       * For arranging some elements, it is useful to know the total unioned area of every element.
       * This Rect can be used to right-align or center-align, etc, elements within an area.
       *
       * @this {PanelLayout}
       * @param {Panel} panel Panel which called this layout
       * @param {Rect} ar arranged bounds of the panel
       * @param {Array.<GraphObject>} elements Array of Panel elements
       * @param {Rect} union rectangle, if properly constructed in {@link #measure}, that contains the expected union bounds of every element in the Panel.
       */
      PanelLayoutCascading.prototype.arrange = function(panel, elements, union) {
        var l = elements.length;
        var x = 0;
        var y = 0;
        for (var i = 0; i < l; i++) {
          var elem = elements[i];
          var mb = elem.measuredBounds;
          this.arrangeElement(elem, x, y, mb.width, mb.height);
          /*
          * By incrementing the arranged x and y by the width and height, we arrange each object in a diagonal fashion:
          *  A
          *    B
          *      C
          *        D
          */
          x += mb.width;
          y += mb.height;
        }
      }

      // Name and register the PanelLayout, so we can reference it in go.GraphObject.make:
      go.Panel.definePanelLayout('Cascading', new PanelLayoutCascading())

      // define a simple Node template
      myDiagram.nodeTemplate =
        $(go.Node, "Auto",
          $(go.Shape, { fill: "transparent" }, new go.Binding("stroke", "color")),
          $(go.Panel, "Cascading",
            $(go.Shape, "RoundedRectangle", { width: 20, height: 20, fill: go.Brush.randomColor(), strokeWidth: 0 }),
            $(go.Shape, "Diamond", { width: 25, height: 25, fill: go.Brush.randomColor(), strokeWidth: 0 }),
            $(go.Shape, "Circle", { width: 25, height: 25, fill: go.Brush.randomColor(), strokeWidth: 0 }),
            $(go.Shape, "TriangleDown", { width: 20, height: 20, fill: go.Brush.randomColor(), strokeWidth: 0 })
          )
        );

      myDiagram.model = new go.GraphLinksModel(
        [
          { key: "Alpha", color: "lightblue" },
          { key: "Beta", color: "orange" },
          { key: "Gamma", color: "lightgreen" },
          { key: "Delta", color: "pink" }
        ],
        [
          // no links
        ]);
    }
  </script>
</head>
<body onload="init()">
<div id="sample">
  <!-- The DIV for the Diagram needs an explicit size or else we won't see anything.
       This also adds a border to help see the edges of the viewport. -->
  <div id="myDiagramDiv" style="border: solid 1px black; width:400px; height:400px"></div>
  <p>
    This sample demonstrates creating a simple custom <a>PanelLayout</a>. It merely cascades the elements diagonally,
    as if combining a Horizontal and Vertical panel.
  </p>
  <p>
    Creating your own Panel layouts is very uncommon, and you should not need to create your own to use GoJS effectively.
    However there may be custom applications that require creating a custom Panel layout.
  </p>
</div>
</body>
</html>
